Solubility enhancement of glibenclamide in choline-tryptophan ionic liquid: Preparation, characterization and mechanism of solubilization

A new ionic liquid solvent was prepared from choline as a cation and tryptophan as the anion. The produced ionic liquid was characterized by NMR, UV and HPLC. The obtained solvent was shown to form in a ratio of 1:1 (choline: tryptophan). The produced solvent was shown to increase the solubility of the low water solubility drug glibenclamide. The mechanism of the observed solubility enhancing effect of the drug was investigated and it did not seem to be simply due to increase in the pH of the medium. The most likely mechanism of increase in the solubility of glibenclamide (Glib) is the formation of complex hydrogen bonds and π-π interaction of the aromatic rings.